Insecticide



Patented Apr. 24, 1945 INSECTICIDE Samuel 1. Gertler and Herbert L. J.Haller, Washington, D. 0., assignors to Claude R. Wickard, as Secretaryof Agriculture of the United States of America, and his successors inoilice No Drawing. Application September 4, 1942, Serial No. 457,295

(Granted under the act of March 3, 1883, as

1 Claim.

amended April 30,1928; 370

This application is made under the act of March 3, 1883, as amended bythe act of April 30, 1928,-

and the invention herein described and claimed, if patented, may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment to us of anyroyalty thereon.

This is a continuation in partof our application for patent filedOctober 9, 1940, Serial No. 360,360.

This invention relates to materials for destroying and checking thegrowth or multiplication of living plant and animal organisms that areeconomically injurious to man.

An object of this invention is to provide materials suitable for use asinsecticides.

Another object of the invention is to provide such materials which willnot cause injury to foliage when dusted or sprayed on delicatevegetation, such as bean plants, peach trees; plants grown under glass,and so forth.

Another object of the invention is to providematerials of the typementioned which are relatively nontoxic to man, and domestic animalswhen taken by mouth, and which can be used in place of lead arsenate andother arsenicals for destroying insects, without leaving harmfulresidues on fruits and vegetables.

We have found that substances belonging to the class of organiccompounds known as semicarbazones have a specific toxic effect uponinsects, and our invention embraces the application of said substancesto the destruction of insects.

Semicarbazones are formed by the condensation of ketones withsemicarbazide. Suitable products according to this invention aresemicarbazones having the formula:

where R represents a cyclo-aliphatic radical,

which may have a methyl substituent.

These products may be dissolved in a suitable solvent or emulsified witha suitable agent or adsorbed on a suitable powder or dust, such as clay,

Example 1 Cyclopentanone semicarbazone was found to be concentration of0.10%. When fed to Hawaiian beet webworm larvae of the fifth instar onSwiss chard leaves, it showed a much higher toxicity after 48 hours thanderris. It also compared favorably with lead arsenate against thecoclling moth. When sprayed on squash plants and fed to the fifth instarof the melon worm it gave as high a kill in the same concentration aftertwo days as derris gave after four days. The compound, dusted on Swisschard leaves and fed to the fifth instar of the Southern beet webwormgave 100% kill in 48 hours.

Example 2 Cyclohexanone semicarbazone was toxic to newlyhatchedscrewworm larvae at a concentration of 0.05%. When dusted onSwiss chard leaves and fed to the fifth instar of the Hawaiian beettoxic to newly hatched screwworm larvae at a II webworm it showed killin 48 hours. When dusted on collard leaves and fed to the crossstripedcabbage worm of the fifth instar, 100% kill was obtained in 48 hours,whereas derris had no effect at all in this period of time. When dustedon Swiss chard leaves against the southem beetwebworm of the fifthinstar, 100% kill was obtained in 48 hours. Melon worm of the fourthinstar when fed pumpkin leaves dusted with this compound showed a 100%mortality in 72 hours.

Example 3 1 Methylcyclohexanone semicarbazone, dusted on collard leaves,when fed to the southern army worm of the fourth instar, gave a 100%kill in 48 hours.

The compounds and examples above are given by way of illustration andnot by way of limitation. The examples are not to be construed aslimiting either the method of application of the insecticide or thekinds of insects to which it may be applied.

Having thus described our invention, we claim:

The method of controlling insects comprising exposing the insects to acompound of the general formula where R represents a member chosen fromthe group consisting of a cycle-aliphatic radical and a cycle-aliphaticradical having a methyl substituent.

SAMUEL I. GERTLER HERBERT L. J. HALLER.

